Process for the co-oligomerization of conjugated unsaturated fatty acids or their esters with indene and/or coumarone



United States Patent US. Cl. 260-407 9 Claims ABSTRACT OF THE DISCLOSUREConjugated unsaturated fatty acids and their esters are co-oligomerizedwith indene and/ or coumarone at a temperature of 40 to 180 C. in thepresence of an acid or Friedel-Crafts catalysts.

The present invention relates to a process for cationicco-oligomerization of conjugated-unsaturated fatty acids or their esterswith indene and/or coumarone.

The conversion to coumarone resins of the light oil fractions from coaltar which are commonly designated as Losungsbenzol II or solventnaphthas having boiling ranges of from 150 to 200 C., and which containconsiderable quantities of indene and somewhat lower amounts ofcoumarone with acid or Friedel-Crafts catalysts is known. It is alsoknown to boil the coumarone resin with drying oils such as linseed andto use the boiled product as a raw material for lacquers. Furthermore,it has been proposed to react unsaturated fatty acids and drying orhalf-drying oils with indene by heating. The mechanism of this reactionand the chemical structure of the products obtained have beenenlightened by H. P. Kaufman and H. Bruning and described in Fette,Seifen, Anstrichmittel, 62 (1960), page 1146. According to theseauthors, the reaction is a diene synthesis in the sense of Diels-Alderwherein from one molecule each of indene and conjugated-unsaturatedfatty acid a monocarboxylic acid derivative of tetrahydrofluorene isformed. Thus beta-eleostearic acid yieldsl-(n-hexen-l-yl)-4-(carbmethoxy-n-heptyl) 1,4,10,11 tetrahydrofluorene,and 9,12- linolic acid yields 1 n heXyl-4-(carbmethoxy-n-heptyl)-1,4,10,1l-tetrahydrofluorene. In these reactions, indene functions as adienophilic reactant. In the case of 9,12- linolic acid, the acid isconverted first to the corresponding conjudiene fatty acid, which isthen subjected to the diene synthesis with indene. Accordingly, it isalso possible to react drying and half-drying oils containingisolated-unsaturated fatty acids in a triglyceride bond such as linseedoil, soya oil, sunflower oil and the like in the sense of this reactionmechanism by heating them with indene to elevated temperatures, wherebyuseful raw ma terials for lacquers are obtained.

N. C. Deno has proposed in Journ. Amer. Chem. Soc. 72 (1950), page 4057,to react lower molecular unsaturated acids and their derivatives, e.g.,sorbic acid and muconic acid, with indene and coumarone yielding alsoDiels-Alder products. Finally, it is known from German Patent 1,110,865,German application DAS 1,161,026,

3,441,577 Patented Apr. 29, 1969 'ice and the publication by A. Hengleinand H. G. Stolzenbach in Makromolekulare Chemie, 44-46 (1961), page 138,to add acrylic acid or lower molecular dicarboxylic acid anhydrides suchas maleic acid anhydride, itaconic acid anhydride and citraconic acidanhydride to indene or coumarone.

It has noW been found that conjugated-unsaturated fatty acids or theiresters or fatty acids or ester mixtures containingconjugated-unsaturated fatty acids can be cooligomerized with indeneand/or coumarone by cationic reaction. The process of the inventioncomprises reacting in the presence of an acid catalyst or catalysts ofthe Friedel-Crafts type one mol of the conjugated, unsaturated fattyacids or esters of the acids with from 0.5 to 20 mols of indene and/orcoumarone. To prevent the formation of any free radicals which otherwisemight affect the result, the reaction is conducted in the presence of aphenolic inhibitor.

According to a preferred embodiment of the process of the invention,isomerized monoesters of half-drying oils such as isomerized soya oilfatty acid methyl ester, isomerized safilower oil fatty acid methylester and the like containing 40 to of conjugated-unsaturated fatty acidin ester bond and indeneand/or coumarone-containing hydrocarbon mixturessuch as the coal tar oil fractions designated as Losungsbenzol II orsolvent naphtha are used.

The isomerized fatty acid monoesters used as starting material areobtained from isolated-unsaturated fatty acid monoesters according toour United States Patent No. 3,162,658, Dec. 22, 1964, to whichreference is made. As stated in said patent, the fatty acid ester is anester of a hydrocarbyl alcohol having 1 to 18 carbon atoms. The fattyacid monoesters are mixed with indene and/or coumarone or thecorresponding amounts of Losungsbenzol II in a ratio of 0.5 to 20 molsof indene and/or coumarone per mol of conjugated-unsaturated fatty acidor its monoester and heated in the presence of acid catalysts, e.g.,acid activated bleaching earth, with stirring and gradual temperatureincrease until in the temperature range between 40 and C. theco-oligomerization commences. This stage is indicated by the spontaneoustemperature increase of the reaction mixture. For completion of thereaction, the mixture is heated-if necessary with a temperature increaseup to a maximum of C. When using Losungsbenzol II, however, thetemperature limit is its boiling point. Heating is continued underreflux until there is no change in the viscosity of the reactionmixture.

In order to eliminate the catalytic influence of peroxides and therewitha possible undesirable radical reaction, the conversion is carried outin the presence of small amounts of phenolic inhibitors such ashydroquinone, butyl catechol and the like. In general, the reactionrequires 1 to 4 hours.

After the catalyst has been removed by filtration or by washing, thefatty acids which do not participate in the reaction, namely saturatedand monounsaturated fatty acids, are removed by distillation underreduced pressure. When using Losungsbenzol II the reacted hydrocarbonsderived from Losungsbenzol II, mainly higher benzene homologues, areremoved in the same manner. Depending upon the proportions of theoriginal components, the residues are liquid to highly viscous to solidresinous homogeneous masses, which comprise in large part polybasiccarboxylic acids together with monocarboxylic acids and arecharacterized by their acid number or saponification number. Theproducts obtained with a low molar ratio of the reaction components canbe distilled without decomposition under high vacuum.

The process of the invention is applicable only toconjugated-unsaturated fatty acids and their esters: not toisolated-unsaturated fatty acids and their esters. Under the conditionsof the process, a homo-oligomerization of the single reactants ispractically excluded. This is shown by the very small amounts ofunsaponifiable components present in the products obtained by theprocess of the invention. This, and the acid catalysts or Friedel-Craftscatalysts which are used as well as the necessity to exclude peroxideswhich could act as catalysts in the sense of a free-radical reactioncharacterize the process as a cationic co-oligomerization. Accordingly,the products obtained by the process of the invention are mixtures ofisomeric monoand polycarboxylic acids or their esters. Typical examplesof such acids, starting, e.g., from 9,11-

linolic acid, have the following structural formula: I. CH3(CHj3HCH=CH(CH2):C00H

1 H H CH2 11 HO n=0 or integer.

n=integer.

Thus the new products obtained by the process of the invention differsubstantially from the known diene adducts as well as from the additionproducts formed by radicalic reactions, which are all monocarboxylicacids.

The main advantage of the present invention is that it permits theaddition of about 15 to 700 parts by weight of indene and/or coumaroneto 100 parts by weight of conjugated-unsaturated fatty acids or theiresters to form chemically defined monoand polycarboxylic acids or theiresters which due to their favorable properties are useful for a greatvariety of applications.

In contrast to coumarone resins and their hitherto known combinationproducts with unsaturated fatty acids and drying or half-drying oils,the products obtained by the process of the invention, surprisingly,exhibit an outstanding light stability. Therefore, they are especiallysuitable for the manufacture of nonyellowing lacquers and coatings, thechemical and mechanical properties of which can be widely varied andadapted to the desired properties by selection of the molar ratio ofindene/conjugated-unsaturated fatty acids. A further advantage of theinvention is that a ratio of 0.5 to about 2 mols indene and/or coumaroneper mol conjugated-unsaturated fatty acid, oligomeric dicarboxylic acidsare obtained as a main product which due to their bifunctional characterare accessible to polyaddition or polycondensation and can be usedtherefore for the manufacture of plastics, e.g., polyarnides. In theform of their hydroxy group-containing polyesters, they are espciallysuitable for the polyaddition with polyisocyanates, whereby rubber-likemasses or foams are obtained.

EXAMPLE 1 600 g. of isomerized sunflower oil fatty acid methyl estercontaining 65% conjugated-unsaturated fatty acid methyl ester (about 1.3mols), 116 g. of indene (1 mol), 6 g. of acid activated bleaching earthand 0.5 g. of hydroquinone were heated with stirring in an atmosphere ofnitrogen; the indene was dissolved within a short time. After themixture had reached a temperature of about C., a brownish discolorationof the catalyst was observed. At the same time, the temperaturespontaneously increased to C. within a few minutes. The reaction mixturewas maintained at 140 C. for several hours; during this time samples forviscosity measurements were taken at half hour intervals (Hopplerviscosimeter, 50 C.). In the course of one hour, the viscosity of themixture increased continuously, whereas in the following 3 hourspractically no further increase of viscosity was observed. After coolingto about 80 C. and following the removal of the catalyst by filtration,the mixture was subjected to fractional distillation to separate thefatty acid methyl esters which had not participated in the reaction.These proved to be mainly oleic acid and palmitic acid methyl esters,and possibly some unreacted indene. In a boiling range of 180 to 190 C.at an initial pressure of 5 torrs and a final pressure of 1 torr a totalof 245 g. distillate corresponding to 34.2% was obtained showing asaponifi cation number of 185 and containing 1.2% of unsaponifiablematter. The distillation residue weighing 470 g. corresponding to 65.8%had a saponification number of 146 and contained 2.2% of unsaponifiable.The free total fatty acids recovered from a part of this residue had asaponification number of 156. 100 g. of the distillation residue weresubjected to fractional distillation at 0.1 torr. The boiling ranges andcharacteristics of the single fractions are shown in the followingtable:

range of to 201 C. and containing 63.3% polymerizable matter comprisinga major portion of indene and a minor portion of coumarone was usedtogether with isomerized safflower oil methyl ester containong 66% ofconjugated-unsaturated fatty acid methyl ester. The catalyst used wasacid acivated bleaching earth in an amount of 2%, based on the totalbatch, and the inhibitor used was di-tert.-butyl-p-cresol (0.05%). Thereaction time amounted to 4 hours and the reaction temperature was heldto 180 C. max. All other working conditions were the same as used inExample 1 with the exception that, when distilling the co-oligomerisate,the hydrocarbons and fatty acid methyl esters were recovered in separatefractions. The following table shows typical batches lected from theclass consisting of hydroquinone, butyl catechol, anddi-tertiary-butyl-para-cresol.

Percent Yield Molar Ratio (a) hydrocarbon Batch of indene/ (b) monomeric(a) g. of ester conjugated- A. esters Consistency Saooni- (b) g. ofLosungsunsaturated (c) co-oligomerie (softening fication benzol II fattyacid RA. es rs point in 0.) Number 600 abt. 1:2 (21) 6 (b) 117 (b) 25(c) 65 (a) 600 abt.1:1.4 (a) 9 (b) 185 (b) 29 (c) 63 600 abt. 1.511 (a)14 (b) 390 (b) 22 (c) 64 (a) 300 abt. 7:1 (a) 31 (b) 910 (b) 7 .0" o111.5 (0) 62 Semi-Solid 63. 9

(a) 154 abt. 13:1 (a) 32 Liquid (b) 800 (b) 000 d 93.5

( 77 abt. 20:1 (a) (b) 900 (b) We claim: 5. A process according to claim11 wherein said sub- 1. Process for the cationic co-oligomerization ofconjugated, unsaturated fatty acids with a compound selected from theclass consisting of indene, coumarone, and mixtures thereof, whichcomprises reacting a substance selected from the class consisting ofconjugated, unsatlrated fatty acids and esters of such acids withhydrocarbyl alcohols having 1 to 18 carbon atoms in the proportions of 1mol of said acid substance to from 0.5 to 20 mols of the said indeneand/or coumarone compound, conducting the reaction at temperatures from40 to 180 C. in the presence of a catalyst selected from the groupconsisting of acid and Friedel-Crafts catalysts, and a phenolicinhibitor of free-radical reaction, for a time suflicient to bring abouta stable, increased viscosity in the reaction mass.

2. Process according to claim 1 wherein the reaction is caused to takeplace under an inert atmosphere.

3. Process according to claim 1 wherein, following the reaction, thecatalyst is separated from the reaction mass and thereafter, thecatalyst-free mass is subjected to distillation under reduced pressureto remove non-reacted components.

4. Process according to claim 1 wherein the conditions establishingcationic co-oligomerization are secured by conducting the reaction inthe presence of a catalytic amount of an acid-treated bleaching earthcatalyst, and free-radical type reaction is inhibited by the presence ofan effective fractional percent of a phenolic inhibitor sestance is amethyl ester.

6. A process according to claim 5 wherein said substance is a member ofthe group consisting of the methyl ester of isomerized soya oil fattyacids, isomerized safliower oil fatty acids and isomerized sunflower oilfatty acids.

7. A process according to claim 1 wherein said compound is indene.

8. A process according to claim 1 wherein said compound is coumarone.

9. A process according to claim 1 wherein said compound is a mixture ofindene and/ or courmarone.

950,602 2/1964 Great Britain. 1,007,914 10/1957 Germany.

OTHER REFERENCES Kaufman et 1.: Fette. Seifen. Anstrichmittel, vol. 62(1960), pp. 1146-52.

ALEX MAZEL, Primary Examiner.

R. T. GALLAGHER, Assistant Examiner.

U.S. Cl. X.R.

